The subject matter disclosed herein relates to air conditioning and pressurizing systems for an aircraft, and more specifically, to adjusting cabin pressure based on ambient conditions to achieve a target aircraft inflow.
Fresh air flow and temperature control within an aircraft is controlled by an air conditioning pack. The fresh air flow is provided as hot compressed air by a flow source. The air conditioning pack performs cooling of the air to regulate the temperature in the flight deck and cabin. The required inflow is typically based on the number of occupants within the aircraft. The amount of flow that can be produced by a flow source is dependent on ambient conditions such as ambient pressure, aircraft speed, and ambient temperature. For a flow source that is operating at its capacity, a contemporary method for increasing fresh flow is to reduce the backpressure of the air condition pack downstream of the flow source. The reduction of backpressure is typically achieved by opening bypass valves within the air conditioning pack. However, while the use of bypass valves will result in increased inflow, it can also result in increased cabin temperatures because the hot compressed air from the flow source is bypassing the cooling capability of the air condition pack.